Water quality

If you have any problems with water quality, please call our 24hrs Emergency Line 62 62 400 or send an e-mail to tvesi@tvesi.ee
Please include your contact number in the e-mail so that we could contact you for more information if needed.We continuously carry out maintenance works to improve water quality and monitor water quality by taking water samples according to the plan approved by the Health Board.
A short-term fluctuation of water quality may be caused by an abrupt abstraction of water from hydrant by our emergency unit (rapid closing and opening of a large amount of water flow results in hydraulic shock in the pipeline, which may make the sediment accumulated on pipes’ walls move).If needed, we also carry out pipeline maintenance from the connection point to the house. This service is free for our customers. Maintenance of service pipes is necessary because during the fixing of emergencies or other activities small particles may accumulate on pipe walls and flushing the service pipe helps to get rid of them.

We remind you that:

  • Old and unmaintained pipeline has a great impact on water quality.
  • If water in the pipes inside the house warms up, which might especially happen when consumption is low, then this might also influence the odour and taste of drinking water.
  • If the temperature rises, reactions in the pipeline intensify, e.g. solubility of substances from pipe surfaces.

In order to have a better result, specialists recommend to let the water run for 1-2 minutes before drinking it.

Analyses provided by our Laboratories to legal persons

We provide all drinking water analyses and most of the ordinary sewage and wastewater analyses. The ordinary tests are:

  • Drinking water analysis for catering companies (odour, taste, colour, turbidity, conductivity, ammonium, Coli-bacteria and Escherichia coli).
  • Drinking water analysis for the issue of a using permit fo a building (odour, taste, colour, turbidity, conductivity, ammonium, Coli-bacteria and Escherichia coli).
  • Drinking water quality tests within the drinking water monitoring programme approved by the Health Board (ordinary and in-depth analyses. If the in-depth analysis package is ordered, we will arrange the tests for pesticides and PAHs from the laboratory, which suits the client.).
  • Drinking water source quality tests
  • Monitoring surface water quality in water bodies
  • Chargeable parameters in wastewater
  • Testing of the cooling water or process water of industrial equipment
  • Testing of wastewater sludge (as per the Minister of Economy’s Regulation no. 78 “Requirments for the use of wastewater sludge in agriculture, greening and recultivation”)

Analyses provided by our Laboratories to private persons

Private persons usually need the water in their residential building or in a cottage well to be tested. We provide the domestic clients with the same services that we provide to commercial clients. However, we recommend the clients to ask our advice on the parameters to be analysed, because the laboratory services might be overly expensive for a private person. Based on the best practice we recommend:

  • Microbiological purity of water is the most important indicator: Coli-bacteria and Escherichia coli, colony count 22 °C, enterococci.
  • Primary chemical parameters: oxidisability, ammonium, nitrate, nitrite.
  • Parameters of natural origin that are often problematic in Estonia: iron, manganese, fluoride.
  • Limescale problems: total hardness, alkalinity (temporary hardness), conductivity, pH
  • Components of mineral content in water: chloride, sulphate, calcium, magnesium, sodium, potassium.
  • In case of specific problems ohter analyses may become necessary – heavy metals, organic pollutants etc.

How much does a water analysis cost?

The price of water analyses depends on the parameters to be tested, see the price list of laboratory services.

How to place an order?

To place an order please conact us by e-mail or phone: labor@tvesi.ee or 62 62 585 (drinking water), 62 62 481 (wastewater).

How is the sampling done?

Sampling techniques are crucial to get reliable results to water analyses. The test results are legally valid only if the sampling has been performed by an accredited sampler. We are also able to provide the relevant service in Tallinn or its surroundings (see IPrice list of laboratory services).

If you still decide to do the sampling by yourself, please follow the instructions below:

  • Fetch specific bottles for sampling from the Laboratory.
  • Clean the outer surface of the faucet. If the faucet has an aerator at the end, remove it. For microbiological analysis, sterilize the end of the faucet with spirits or isopropanol.
  • Let the water run ~5 minutes.
  • Adjust the flow (so it does not splash).
  • Place the bottle under the faucet, but avoid the mount of the bottle contacting the faucet.
  • For chemical analyses rinse the bottle and cap 2-3 times with sample water, fill it to the top and close tightly.
  • The bottle used for microbiological analysis is sterile. Therefore, do not touch the inside of the sample bottle or its cap. Unlike with chemical analysis, do not rinse the bottle or overfill it, but fill the bottle within 2-3 cm from the top.

How to handle the samples?

Samples must be delivered to the laboratory as soon as possible after collection, preferably in 6 hours, but not later than 24 hours after the collection of samples. Store the samples in a refrigerator at 1…5 °C, use a cooler to transport the samples if possible.

Where to deliver the samples?

Drinking water samples are accepted by the Water Laboratory at Ülemiste Water Treatment Plant (Järvevana tee 3).

Wastewater, soil and sludge samples are accepted by the Wastewater Laboratory at Paljassaare Wastewater Treatment Plant (Paljassaare põik 14).

When are the samples accepted?

Samples are accepted from Monday to Thursday 8.30 – 15.00. We recommend you to bring the samples as early in the week as possible.

When would the results be ready?

Usually the Laboratory issues the results of the samples received at the beginning of the week at the end of the same week. Specific analyses may take longer time.

How is the billing done?

The client will receive an invoice after a number of work days as of the issue of the test results. The invoice can be paid via a bank transfer.

How to interpret a water analysis report?

  • The report presents the test result and in case of a drinking water analysis the report also presents the limit values established by the applicable drinking water quality requirements. If the test result is lower or equal to the limit value, the drinking water quality complies with the requirements for that particular parameter. If the test result exceeds the limit value, the drinking water quality fails to comply with the applicable requirements.
  • Some parameters do not have a limit value  – it means that the parameeter poses no danger to public health. For instance, hardness can cause the formation of scale deposits in domestic appliances it is not a health risk.
  • Some results have the sign „<“ them. It means that the parameter is below the limit of detection of the selected method of analysis. Due to the fact that the selected methods are specifically suitable for water analysis, the described result mostly represents a very low level, which meets the requirements.
  • The report also displays a reference to the method of analysis used for a particular parameter. For instance, EVS EN-ISO 7027 means the standard method published by the International Organization for Standardization (ISO), which has been adopted as an European Union standard (EN) and also Estonian standard (EVS).

How reliable are the test results from the Laboratory?

The laboratories performing both drinking water analyses and other water analyses must be accredited in Estonia. This means that the laboratory is subject to certain quality standards and regular audits by independent experts. AS Tallinna Vesi’s laboratories have been accredited since 2001. The accrediation scope of the laboratories has been set out in the Annex to the Accreditation Certificate, which can be downloaded on the website of Estonian Accreditation Centre.

Drinking water quality is checked based on the Regulation No. 82 issued by the Ministry of Social Affairs “Quality and control requirements for drinking water and methods for testing”.

Drinking water which is treated from surface water needs to be disinfected before it is pumped into the public water network, for which purpose chlorine compounds are used. The concentration of free chlorine in water discharged from the water treatment plant shall be as much as 1 mg/l (Ministry of Social Affairs Regulation No 61). Drinking water quality requirements are in accordance with EC drinking water directives and WHO (World Health Organisation) requirements. The aim is to ensure that the quality of drinking water is maintained throughout the supply system and that the water is safe to drink.

The concentration of fluoride in drinking water produced in Ülemiste water treatment plant is low (0.04 – 0.2 mg/l). Drinking water in Tallinn’s groundwater areas (Nõmme, Merivälja, Tiskre, Harku and Saue) contains more fluoride, usually in the range of 0.4-0.8 mg/l. Everywhere, fluoride is naturally present in the water, it is not added or removed in the course of water treatment process.
Fluoride concentration in the water of Ülemiste water treatment plant is checked once a month and that in groundwater from bore wells once a year.

Water hardness is caused by calcium and magnesium salts dissolved in water. Drinking water in Estonia is mostly hard as we live on limestone soil and the same limestone makes our drinking water hard.
The degree of water hardness is classified as follows:

Soft: 0…1 mg-ekv/l
Moderately soft: 1…2 mg-ekv/l
Slightly hard: 2…3 mg-ekv/l
Moderately hard: 3…4 mg-ekv/l
Hard: 4…6 mg-ekv/l
Very hard:  >  6 mg-ekv/l

As seen from the following table, there are several units of measurement in the world for determining the hardness of water:

Unit mg/l Ca mg-ekv/l mmol/l °DH (GER) °Clark (UK) F degree (FRA) ppm (USA)
1 mg/l Ca 1 0,05 0,025 0,14 0,175 0,25 2,5
1 mg-ekv/l 20 1 0,5 2,8 3,5 5 50
1 mmol/l 40 2 1 5,61 7,02 10 100
1 °DH (GER) 7,14 0,357 0,178 1 1,25 1,78 17,8
1 °Clark (UK) 5,72 0,286 0,143 0,80 1 1,43 14,3
1 F degree (FRA) 4 0,2 0,1 0,56 0,7 1 10
1 ppm (USA) 0,4 0,02 0,01 0,056 0,070 0,1 1

The hardness of water produced in our water treatment plant depends on Lake Ülemiste and therefore fluctuates on a seasonal basis: it is higher in winter and spring (up to 5,5 mg-ekv/l) and lower in summer and autumn (from 3,5 mg-ekv/l). In groundwater areas (Nõmme, Merivälja, Tiskre, Harku and Saue), the value of water hardness varies in the range of 2…5 mg-ekv/l.